Counterbalance



Oct. 4, 1932. T. o. DUCKWORTH ET AL ,8 0

COUNTERBALANCE Filed Oct. 1'7. 1930 7 A ,a/ I I" G 8 0. 0M a W WWPatented Oct. 4, 1932 T UNITED stares PATEN- mnnornrus o. nuoKwoR'rH ANDFRANCIS ii. nons'rooL, or SALT LAKE orrY, UTAH couNT'ERBALANoEApplication filed October 17,1930. Serial No. 489,282.

This invention relates to an. improvement in a counter balance. And oneof .its objects is to provide a counter balance of new principle anddifferent from anyknown counter 5 balance now in use. v V

Anotherobj-ect of this invention is to provide a counter balanceentirely controlled by air pressure. a, 7

Another object of this invention-is to pro? 10 vide a counter balancewith which the dangerous walking beam and sliding weight now used areabolished. i

Another object of this invention is to provide a counter balancecontrolled by air and constructed in such a mannerthat a very smallamount of power will be required to operate the weight.

Another object of this invention is to pro vide a counter balance,comprisingv a plurality of cylinders having pistonsytherein with whichan air cushion will be placed against the piston in the lowering of theweight orlt'he load .to bejlowered, and to place an air lifting pressureagainst the piston in 26 the lifting of the weight or load to be raised.

'With these and other objects in view the invention consists of thefollowing novel construction as hereinafter described and claimed.

In the accompanying drawing forming a part of thisspecification and inwhich corre s onding parts are denoted by like reference characters, isillustrated the preferred form of embodiment of the invention capable ofcarrying the same into practical operation, it being understood that theinvention is not necessarily limited thereto, as various changes inshape, proportions and general assemblage of its parts may be resortedto without de- 40 parting from the principles'of the invention, orsacrificing any of its advantages, and the right is therefore reservedfor making all the changes and modifications which will fall within thescope of the invention and claim made therefor,

The invention will be described as applied to the Duckworth pump rodlifts, Serial No. 458,103, filed May 31, 1930, or Serial No. 383,949,filed Aug. 6, 1929. When Serial N o.

- 458,103 is used the counter balance 7 and the support 8 are omitted,while it is shown on the Duckworth pump rod lift it can be applied toany other design of pump rod lift,

Referring to the drawing: 7 F i-gurel is a plan view of the'inventionshowing it in combination with the Duckworth pump rod lift. V Fig. 2 isa front view of Fig. .1, showing one set of cylinders partly in sectionto show the construction of the cylinders and pistons. The referencecharacter A denotes a floor or base. plate upon which theinvention andpump rod lift B rests." Gdenotes air tan-ks which are connected togetherby a pipe D in such a mannerthat eachtank contains thesame air pressure.On top of each tank isplaced a safety valve 1 through which all overload of air escapes. V

The cylinders E and Fare secured to their base G by welding or othermeans. F The base G has an aperture '52 therein into which is placed oneend of a pipe H and the other end of the pipe H is secured within thetanks C, thus making a solid air chamber out of the cylinders E, pipesand the tanks C. The tank C must be not less than forty times the sizeofthe cylindei to give the required air space, so that there will be noback pressure on the piston 3 when the piston is being moved H to thelower endof the piston'E andbut a "80 very small change in pressure whenthe piston 3 is moved :t'othe upper end of the cylin- EderE. Thecylinders E are counter balancing cylinders which in combination withthetanks C counterbalance the load carried by the pump jrod. I Withinthe cylinders is apiston 3'having one end of a piston rod 8 securedtherein, U the other end of said rod being secured to a 90 cross head J.3 I a The cylinder F which has a pistont therein also has valves 5passing therethrough to allow air toenter said cylinder on the inwardstroke of said piston. One end of a piston rod 6 is secured to saidpiston'and the other'end 'thereof beingl secured to the cross head J. Inthe inward strokeof said piston l'theairwithin the cylinder F is com-ipressed and forced out of the cylinder through valve 7 in the bottomthereof into opening 9 into cylinder E, thus keeping the air in thetanks at the required pressure at all time. And in the event that thepresthrough the relief valve 1 of the tank C.

On the upper; ends of the cylinders E and v placed through an aperturein the forkslet' of the'cross head J. They a'l so answer as guides forthe crosshead J.

pistons 8 and 6, comprises a *support- 13. having notches thereinthrough which is placed horizontal' nioving rods 15 .which are securedintolthe notches bya'platej16 securedto the upright. support 13. 1 Oneach end of the rods 15 arefsecuredv vertically placed rods 17." Eachendof, theivertically placed rods has a roller bearing 18V'thereo-n. 'Theroller bearingin the, lowenend of the rods 17 roll back'and forth onatrack 19 which is secured to the supportl13 by bolts 90, The rollerbearings on the upper ends of the rods 17 roll back and forth under atrack 20 which is secured to the support 18 by bolts 91."; v 1 1 Ahousing 21 operating up and down on the vertical rods 17 has an endlessrack 22 therein secured to the inner wall thereof. A

port '13, said pinion-meshing with said endless rack; The shaft 24 has adriven sure would become excessive it will pass out o pinion 23 withinsaid housing secured to oneend of a shaft 24 passing through said sup'-'weight of the pump rod'M which is in the well N. The pump rod is securedto the cross head in such a manner that it will move up 0nd down withthe cross head.

To illustrate the counter balancing ability of the invention in itsmovements.

Take the piston in the cylinders E to have an'area of 58 square inches,and the air pressure in the tank to be 110 pounds per square inch.'There would be a pressure of 6380 on each cylinder, or-12-760 on'thetwopistonsj This air pressure would hold up a weight of 12760 pounds.The'weight of the pump rod and liquidin the well weighing 13000 pounds,leaves a lifting powerfor the motor to lift of The pump rod lift-B usedto operate the a little better than 240 poundsf' e c .1 The tank orairre'servoir. is first filled with air to the required pressureby' aportableiair. pump tothe pressure required, and .afterthe invention hasbeen placedtin operation it will supply its own air, as stated above; Ia *J p Having thus describedpthe invention what we claim as new anddesire to secure by Let tersPatent,is:' if 1'. a; 1 I

An air counterbalance .for .apump rod comprising a crosshead secured tosaid pump rod, means for reciprocating said crosshead; acounterbalancing unit on each end of said crosshead, eachcounterbalancing' unit :com prising a reservoina main cylinder-incombination lwith; said reservoir,"j an auxil iary supply cylinderhaving a one-way valve at the end thereof in cominunicationiwith saidmain cylinder, pistons in said cylinders and means connecting saidpistons tolsaid crosshead. THEOPHI-US O1 DUCKWORTH.1.-

= FRANCIS L. HORSPOOL.

ingup and down and right and left as shown by dotted lines andarrows93,the. housing being connected, to the cross head by, links ;4 i,r

26. Thus as the housing israised'the cross head will 'beraised to dottedlinesjL which moves the pistons outward in the cylinders p and asthe'icross head is: loweredby the.- housing the pistons are moved inwardof the Y cylinders. c

When the invention is operated as stated above the airinithe tankspassing through V thepipes H enter the cylinders and coming I 5 intocontact with the pistons ,3 always maintain a pressure against the innerside of the pistons, so when the housing. is raised to move j A thecross heads and pistons outward,lthe air under the pistons helpto raisethem.

When the pistons 3 areimoved into the cyl- V I I inders the air withinthe cylinder is forced i 1 back through'the pipe H into thetanks, thusjforminga cushion under the pistons. The 351'. air so' entering andmaintained within the I cyl nders formsthe counter balance for the x;

